Feasibility of using real time "Live 3D" echocardiography to visualize the stenotic aortic valve.

BACKGROUND: Aortic stenosis valve area (AS AVA) using the continuity equation (CE AVA) has limitations. Thus anatomic assessment of AS AVA would be useful.

METHOD: AS AVA was measured using "live three-dimensional (3D)" echocardiography that is a two-dimensional (2D) display of a three-dimensionally acquired 2-3 cm thick pyramidal image. In 52 aortic stenosis patients with CE AVA measurements, attempts were made at measuring AS AVA using 2D echocardiography (2D AVA) and real time, Live 3D echocardiography (3D AVA). 3D AVA and 2D AVA were compared to each other and to CE AVA.

RESULTS: 2D AVA could be obtained in 30 patients (58%) and 3D AVA in 50 patients (96%). Of the 30 patients in whom 3D AVA and 2D AVA were both measured, the correlation was 0.831 (P < 0.001). 3D AVA was smaller in 19 patients. In 17 of these patients, 3D AVA was closer to CE AVA. In two patients, 2D AVA was smaller than 3D AVA and in both patients 3D AVA was closer to CE AVA. The correlations between 2D AVA and CE AVA and 3D AVA and CE AVA were 0.581 and 0.673, respectively (all P < 0.001).

CONCLUSION: A simplified 3D technique that is a "thick slice" 2D examination, can obtain AS AVA more often than a "thin slice" 2D echocardiogram. This 3D AVA correlates well with 2D AVA but is smaller and correlates better with CE AVA suggesting that the effective AS orifice is not planar but is more of a "tunnel" than a "flat ring."